Programming Forums > Application Development > C

bconnor · May 18th, 2006, 9:25 PM

So basically im trying to work on a single player pong game ...

What im struggling with the logic behind the movement of the paddle..

If i just keep pressing the one direction, say a ... that moves fine, though the issue arises when i than press z, rather than moving down just one space, it moves far more than that...

(Toggle Plain Text)

	

/* a = up, z = down */


	int	c, temp, moveA, moveZ;
	temp = 1; 
	moveA, moveZ = 5; 
	
	set_up();

	while ( ( c = getchar()) != 'q' ){
		if ( c == 'a' ){
		clear();
		attron(A_REVERSE);
	
		move(0,LEFT_EDGE+20);
		addstr(" Single Player Pong ");	
	
		move(2,LEFT_EDGE+2);
		addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q ");
	
	
		move(TOP_ROW-1,LEFT_EDGE-1);           	
		hline(' ', LEFT_EDGE + 53);		/* Top Border */
		vline(' ', TOP_ROW + 13);		/*  Left Side  */
	
		move(BOT_ROW+1,LEFT_EDGE); 	  	/* Bottom Border */
		hline(' ', LEFT_EDGE + 52);
		
		moveA = (TOP_ROW + 5)-temp;
		move(moveA,RIGHT_EDGE+1);		  
		vline(' ', (BOT_ROW-TOP_ROW)/3);
		attroff(A_REVERSE);
		getch();	
		if ( c == 'a' )	{
			temp++;
			}
		else {
			moveA = moveA +1;
			}
		}
		else if ( c == 'z' ){
		clear();
		attron(A_REVERSE);
	
		move(0,LEFT_EDGE+20);
		addstr(" Single Player Pong ");	
	
		move(2,LEFT_EDGE+2);
		addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q ");
	
	
		move(TOP_ROW-1,LEFT_EDGE-1);           	
		hline(' ', LEFT_EDGE + 53);		/* Top Border */
		vline(' ', TOP_ROW + 13);		/*  Left Side  */
	
		move(BOT_ROW+1,LEFT_EDGE); 	  	/* Bottom Border */
		hline(' ', LEFT_EDGE + 52);
		
		moveZ = (TOP_ROW + 5)+ temp;
		move(moveZ,RIGHT_EDGE+1);	  
		vline(' ', (BOT_ROW-TOP_ROW)/3);
		attroff(A_REVERSE);
		getch();
		if ( c == 'z' ){
			temp++;
			}
		else{
			moveZ = moveZ -1;
			}
		}

The Dark · May 18th, 2006, 11:06 PM

It looks like your variable "temp" is the position of the bat, when you press "a", you are subtracting from (TOP_ROW + 5), but when you press "z" you are adding it to (TOP_ROW + 5), this means it will jump all over the place. Especially since temp never gets decreased.

My suggestion:
Change the name of "temp" to "batPosition" (or similar). Increment it when the users presses "a" and decrement it when they press "z" then you can always use the same calculation for where to draw the bat. This also means that your two if statements can be merged together. Something like:

(Toggle Plain Text)

  if ( c == 'a')
    batPosition++;
  else if (c == 'z')
    batPosition--;
  ... Drawing code here

I am not sure what these lines of code are for (in red):

(Toggle Plain Text)

    if ( c == 'a' )	{
      temp++;
    }
    else {
      moveA = moveA +1;
    }

It will never get in there, as c is always 'a' at this point, even if it did get in there, moveA is never used again after this point, so there is no point in modifying it.

bconnor · May 18th, 2006, 11:53 PM

Yeah, not sure myself what i was trying to with the code in red, i think possibly it was meant to be elseif statement, though i get the sense my head is somewhere else today, if anywhere at all ...

Quote:

always use the same calculation for where to draw the bat

This going to sound dumb i get the sense, though in what sense do you mean "same", the same as i had, or a calculation that will be same as both..

(Toggle Plain Text)

move((TOP_ROW + 5) + padPosition,RIGHT_EDGE+1);		  
vline(' ', (BOT_ROW-TOP_ROW)/3);

*Sorry its just one of those days...

The Dark · May 19th, 2006, 2:30 AM

Same calculation for both, it doesn't matter whether you are going up or down when you are drawing the bat, it is the location that counts.

May 18th, 2006, 9:25 PM	#1
bconnor Newbie Join Date: Mar 2006 Posts: 9 Rep Power: 0	Help with logic? So basically im trying to work on a single player pong game ... What im struggling with the logic behind the movement of the paddle.. If i just keep pressing the one direction, say a ... that moves fine, though the issue arises when i than press z, rather than moving down just one space, it moves far more than that... (Toggle Plain Text) /* a = up, z = down / int c, temp, moveA, moveZ; temp = 1; moveA, moveZ = 5; set_up(); while ( ( c = getchar()) != 'q' ){ if ( c == 'a' ){ clear(); attron(A_REVERSE); move(0,LEFT_EDGE+20); addstr(" Single Player Pong "); move(2,LEFT_EDGE+2); addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q "); move(TOP_ROW-1,LEFT_EDGE-1); hline(' ', LEFT_EDGE + 53); / Top Border / vline(' ', TOP_ROW + 13); / Left Side / move(BOT_ROW+1,LEFT_EDGE); / Bottom Border / hline(' ', LEFT_EDGE + 52); moveA = (TOP_ROW + 5)-temp; move(moveA,RIGHT_EDGE+1); vline(' ', (BOT_ROW-TOP_ROW)/3); attroff(A_REVERSE); getch(); if ( c == 'a' ) { temp++; } else { moveA = moveA +1; } } else if ( c == 'z' ){ clear(); attron(A_REVERSE); move(0,LEFT_EDGE+20); addstr(" Single Player Pong "); move(2,LEFT_EDGE+2); addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q "); move(TOP_ROW-1,LEFT_EDGE-1); hline(' ', LEFT_EDGE + 53); / Top Border / vline(' ', TOP_ROW + 13); / Left Side / move(BOT_ROW+1,LEFT_EDGE); / Bottom Border / hline(' ', LEFT_EDGE + 52); moveZ = (TOP_ROW + 5)+ temp; move(moveZ,RIGHT_EDGE+1); vline(' ', (BOT_ROW-TOP_ROW)/3); attroff(A_REVERSE); getch(); if ( c == 'z' ){ temp++; } else{ moveZ = moveZ -1; } } / a = up, z = down / int c, temp, moveA, moveZ; temp = 1; moveA, moveZ = 5; set_up(); while ( ( c = getchar()) != 'q' ){ if ( c == 'a' ){ clear(); attron(A_REVERSE); move(0,LEFT_EDGE+20); addstr(" Single Player Pong "); move(2,LEFT_EDGE+2); addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q "); move(TOP_ROW-1,LEFT_EDGE-1); hline(' ', LEFT_EDGE + 53); / Top Border / vline(' ', TOP_ROW + 13); / Left Side / move(BOT_ROW+1,LEFT_EDGE); / Bottom Border / hline(' ', LEFT_EDGE + 52); moveA = (TOP_ROW + 5)-temp; move(moveA,RIGHT_EDGE+1); vline(' ', (BOT_ROW-TOP_ROW)/3); attroff(A_REVERSE); getch(); if ( c == 'a' ) { temp++; } else { moveA = moveA +1; } } else if ( c == 'z' ){ clear(); attron(A_REVERSE); move(0,LEFT_EDGE+20); addstr(" Single Player Pong "); move(2,LEFT_EDGE+2); addstr(" INSTRUCTIONS: (move paddle) A - up, Z - down (quit) - q "); move(TOP_ROW-1,LEFT_EDGE-1); hline(' ', LEFT_EDGE + 53); / Top Border / vline(' ', TOP_ROW + 13); / Left Side / move(BOT_ROW+1,LEFT_EDGE); / Bottom Border */ hline(' ', LEFT_EDGE + 52); moveZ = (TOP_ROW + 5)+ temp; move(moveZ,RIGHT_EDGE+1); vline(' ', (BOT_ROW-TOP_ROW)/3); attroff(A_REVERSE); getch(); if ( c == 'z' ){ temp++; } else{ moveZ = moveZ -1; } }

May 18th, 2006, 11:06 PM	#2
The Dark Expert Programmer Join Date: Jun 2005 Posts: 874 Rep Power: 4	It looks like your variable "temp" is the position of the bat, when you press "a", you are subtracting from (TOP_ROW + 5), but when you press "z" you are adding it to (TOP_ROW + 5), this means it will jump all over the place. Especially since temp never gets decreased. My suggestion: Change the name of "temp" to "batPosition" (or similar). Increment it when the users presses "a" and decrement it when they press "z" then you can always use the same calculation for where to draw the bat. This also means that your two if statements can be merged together. Something like: (Toggle Plain Text) if ( c == 'a') batPosition++; else if (c == 'z') batPosition--; ... Drawing code here if ( c == 'a') batPosition++; else if (c == 'z') batPosition--; ... Drawing code here I am not sure what these lines of code are for (in red): (Toggle Plain Text) if ( c == 'a' ) { temp++; } else { moveA = moveA +1; } if ( c == 'a' ) { temp++; } else { moveA = moveA +1; } It will never get in there, as c is always 'a' at this point, even if it did get in there, moveA is never used again after this point, so there is no point in modifying it.

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May 19th, 2006, 2:30 AM	#4
The Dark Expert Programmer Join Date: Jun 2005 Posts: 874 Rep Power: 4	Same calculation for both, it doesn't matter whether you are going up or down when you are drawing the bat, it is the location that counts.

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Programming Forums > Application Development > C

Help with logic?